As one example of a manufacturing process of a semiconductor device, there is a case where a silicon oxide film is formed on a substrate by supplying, e.g., a silicon-containing precursor gas and an oxidizing gas, to the substrate. At this time, a film can be formed at a relatively low temperature by using, e.g., a catalytic gas, which improves thermal budget of a semiconductor device.
When forming the aforementioned thin film on the substrate, a film quality such as a resistance to wet etching or the like can be improved by adding, e.g., carbon, to the thin film.
However, under a condition of relatively low temperature, a sufficient amount of carbon is not introduced into the film. This often makes it difficult to obtain a thin film having a high etching resistance. Moreover, it is sometimes the case that the thin film added with carbon shows a low ashing resistance.